A semiconductor device such as an MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and an IGBT (Insulated Gate Bipolar Transistor) attains the ON state when a voltage equal to or more than a threshold value is applied to a gate electrode thereof.
A period of time from when a voltage is started to be applied to the gate electrode to when the voltage of the gate electrode becomes equal to or more than a threshold value is proportional to the electrical resistance of the gate electrode. Therefore, in order to operate the semiconductor device at a high speed, the electrical resistance of the gate electrode is preferably smaller.